1. Field of the Invention
The invention relates to retractors that are used in various types of surgeries such as cardiovascular surgery and, more particularly, to a retractor that permits such operations to be conducted with minimal trauma to the patient.
2. Reference to Provisional Application
Reference is made to provisional application Ser. No. 60/042,472, filed Mar. 28, 1997, the disclosure of which is incorporated herein by reference and from which priority is claimed.
3. Description of the Prior Art
In the course of such operative procedures as mitral valve surgery, it is necessary to expose the heart. Such exposure traditionally has been accomplished by performing a sternotomy (cutting an incision completely through the sternum and retracting the sternum). The retraction is accomplished by a retractor that employs parallel grips that engage the edges of the separated sternum. The grips are mounted perpendicularly to a toothed crossbar. One of the grips is fixed to one end of the crossbar, while the other grip is movably mounted to the crossbar by means of a pinion that engages the teeth of the crossbar. Upon rotating the pinion, the movable grip can be moved away from the fixed grip, thereby retracting the sternum so as to expose the heart. A retractor of the type described is shown in U.S. Re. 34,150, issued Dec. 29, 1992 to A. E. Santilli and D. M. Cosgrove III (xe2x80x9cthe ""150 patentxe2x80x9d), the disclosure of which is incorporated herein by reference.
After the sternum has been retracted, it is necessary to retract portions of the heart in order to expose diseased or defective parts thereof. Such retraction has been accomplished by attaching a cardiovascular retractor to one of the grips of the sternum retractor. The cardiovascular retractor, in preferred form, includes a horizontal rod to which retractor blades having elongate handles are attached by means of universal clamps. The rod is spaced above the grip a considerable distance in order to permit the blades to have access to the heart at a favorable angle. The blades can be moved so as to engage portions of the heart to be retracted. Thereafter, upon pulling the blades and locking them in place by tightening the universal clamps, the heart can be retracted in any manner desired and maintained in that position as long as necessary.
The blades in the described construction can be moved back and forth, up and down, side to side, and they can be pivoted about the longitudinal axis of the handle. Such versatility enables the device to be used for virtually any type of heart operation where retraction is required. A preferred example of the device in question is disclosed in the ""150 patent.
While the retractor disclosed in the ""150 patent is effective for retraction of the sternum and subsequent retraction of the heart, unfortunately the operative technique is very invasive. That is, the splitting of the sternum coupled with its retraction is an extremely traumatic procedure. The recovery time from such a procedure can be significant. Further, the patient will experience considerable pain and discomfort during the recovery process. It is possible that the trauma associated with the process can have a negative impact on the patient""s recovery from the operation.
Desirably, a retractor would exist that would permit surgical procedures to be performed that are less invasive than are possible with presently available retractors. Preferably, any such retractor would be relatively small and lightweight compared with prior retractors.
In accordance with the present invention, a new and improved retractor is disclosed that is minimally invasive. The invention also includes a new and improved method of retraction. By using the present invention, the heart can be accessed through a small incision between the ribs on the left side of the chest, usually between the third and fourth ribs. The right side of the chest also can opened in this manner for various purposes such as harvesting the right-side mammary artery. If it is desired to approach the heart through the sternum, only a small opening in the sternum is required. Further, the present invention permits certain heart operations to be performed without the need to stop the heart and use a heart-lung machine. In addition to heart surgeries, the present invention also enables other types of operations to be performed more effectively that has been possible heretofore.
The retractor according to the invention is provided in two embodiments for use in different surgical procedures as the surgeon may determine. In one embodiment, the retractor includes a pair of small grips, or paddles, that are mounted to an elongate crossbar. The grips are disposed at the ends of arms that are connected removably to blocks that are connected to the crossbar. One of the blocks is fixed to one end of the crossbar, while the other block is movable along the crossbar so as to move toward or away from the fixed grip. The movable block is moved along the crossbar by means of a pinion that engages teeth on the crossbar. The pinion has a handle (or wrench) in order to permit the block to be moved readily.
The crossbar in the present invention includes a hinge disposed at a location between its ends and between the spaced grips. The hinge is movable about an axis that is perpendicular to the longitudinal axis of the toothed portion of the crossbar and parallel to, or coincident with, a plane in which the toothed portion of the crossbar lies. Accordingly, the hinge enables one end of the crossbar to be pivoted which, in turn, enables the fixed grip to be pivoted relative to the movable grip. Preferably, the hinge enables the fixed grip to be moved through an angle of +45 degrees and xe2x88x9245 degrees relative to the longitudinal axis of the toothed portion of the crossbar.
The invention includes means for pivoting the fixed grip about the axis of the hinge. The means for pivoting can take two forms. In the first form, a first, vertically extending bracket is secured removably to one of the blocks and a second, vertically extending bracket is secured removably to the other block. An elongate rod having first and second opposed ends is pivotally connected at its first end to the first bracket and adjustably connected at its second end to the second bracket. Preferably, the second bracket includes an opening through which the second end of the rod extends. The second end of the rod is threaded and carries a nut for engaging the second bracket.
When the crossbar is positioned in a straight line, i.e., not pivoted, the rod is parallel to the longitudinal axis of the crossbar. The rod is connected to the brackets such that it is disposed above the crossbar a desired amount. When the nut is tightened and/or when the grips are moved apart, the fixed grip will be pivoted relative to the movable grip.
The invention also includes so-called side arm attachments. These attachments are elongate rods that can be removably attached to either of the arms. The rods enable one or more retractor blades of conventional design having elongate handles to be used to retract portions of the heart. Each retractor blade is connected to a selected rod by means of a universal clamp that encircles the handle of the blade and which is attached to the rod. Each clamp includes a nut that enables the clamp to be tightened or loosened with one hand. The clamps permit the blades to be moved to any position that may be desired by the surgeon.
The invention is especially effective for certain types of heart surgeries when employing a retractor blade known as a stabilizer. The stabilizer in question has an elongate handle to which a pair of spaced, parallel, generally flat fingers are connected at one end. The fingers lie in a plane disposed at an angle of approximately 125 degrees from the longitudinal axis of the handle. The stabilizer enables the heart to be compressed so as to be rendered relatively motionless. The region of the heart between the spaced-apart fingers will be relatively starved for blood, thereby permitting surgery to be performed without the need for a heart-lung machine to stop the heart. In order to accommodate different operative conditions, the stabilizer can be provided with malleable fingers, a malleable neck, or with an adjustable ball and socket connection between the handle and the fingers.
A particularly effective technique for supporting the stabilizer is to provide a housing that can be connected to a selected block. The stabilizer is connected to the housing by a flexible member that can be secured in a rigid position when desired. Preferably, the flexible member includes a plurality of generally tubular members disposed in end-to-end relationship, a cam disposed within the housing, a fitting (to which the stabilizer is connected) disposed at the end of the generally tubular members, and a cable extending through the generally tubular members. Upon activating the cam, the cable will be tightened or loosened, thereby securing the stabilizer in place or permitting it to be moved. An adjustment mechanism also can be provided for pre-tensioning the generally tubular members.
In a second embodiment of the invention, both blocks are movably mounted on the crossbar. This permits each arm with its respective grip to be positioned at any desired location relative to the hinge.
The invention also includes a second form of the means for pivoting the crossbar. The second form includes first and second brackets that are connected to the first and second blocks, respectively. The brackets are connected by a toothed rod, or rack, that is affixed to one of the brackets and which extends through an opening in the other bracket. The other bracket includes a pinion that can be rotated by a wingnut. A spring-biased pawl prevents the brackets from moving away from each other while permitting the brackets to move toward each other, thereby causing the crossbar to be pivoted.
The method according to the invention comprises a particular technique for retracting the patient""s ribs or sternum most effectively. The method in question involves compressing the distal ribs, while retracting and raising the adjacent proximal ribs. This result is accomplished by orienting the crossbar such that the movable grip is on the distal side of the patient.
Initially, the hinge is positioned to provide a straight crossbar and the grips are moved together in order to insert them between the ribs. The means for pivoting is actuated in order to pivot the fixed, or proximal, grip about the axis of the hinge. Then, the grips are moved apart by moving the distal grip along the crossbar. As the distal grip is moved, the grips are spaced further apart and the proximal grip is raised even further. Such retraction provides adequate access to the heart despite the small incision between the ribs.
The retractor according to the invention can be used for operations on either side of the chest. By orienting the crossbar appropriately, the retractor can always be positioned to compress the distal ribs and retract and raise the proximal ribs. A similar result can be obtained with incisions through the sternum, that is, appropriate positioning of the blocks and brackets will enable either side of the sternum to be retracted and raised as may be desired.
As will be appreciated from the foregoing description, the retractor according to the invention is minimally invasive. By using the retractor according to the invention, adequate access to the heart can be obtained merely by making a small incision between two adjacent ribs. There is no need to completely split the patient""s sternum in order to have access to the heart. The foregoing results are obtained by using very small grips and using the retractor first as a rib-spreader (or sternum, spreader) and then as a proximal rib-lifter (or sternum lifter). Once the ribs or sternum have been retracted and raised properly, various attachments can be connected to the retractor for purposes of cardiovascular retraction and other purposes.
The retractor according to the invention also can be used for other types of surgeries, such as spinal implant surgery. The retractor can be used for both anterior and posterior spinal implant surgery. The ability to pivot and displace the fixed grip relative to the movable grip is a significant advantage compared with existing retractors. Further, because the grip-carrying arms are removably connected to the retractor, it is possible to substitute differently configured grips to conduct different types of surgical procedures, to conduct surgical procedures on different sizes of people, or to perform different types of retractions during the course of the same surgical procedure. Such substitutions can be accomplished quickly and easily, thereby enhancing the versatility of the retractor.
The foregoing features and advantages will be apparent from the accompanying drawings and the description that follows.